US4710481A - Method for melting Ti or a high-Ti alloy in CaO refractories - Google Patents

Method for melting Ti or a high-Ti alloy in CaO refractories Download PDF

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Publication number
US4710481A
US4710481A US06/906,487 US90648786A US4710481A US 4710481 A US4710481 A US 4710481A US 90648786 A US90648786 A US 90648786A US 4710481 A US4710481 A US 4710481A
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cao
weight
alloy
melting
refractories
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US06/906,487
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English (en)
Inventor
Toru Degawa
Gen Okuyama
Akio Hashimoto
Seiju Uchida
Kouzou Fujiwara
Makoto Ebata
Takashi Satou
Tohei Ototani
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Mitsui Engineering and Shipbuilding Co Ltd
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Mitsui Engineering and Shipbuilding Co Ltd
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Assigned to MITSUI ENGINEERING & SHIPBUILDING CO., LTD., 6-4, TSUKIJI 5-CHOME, CHUO-KU, TOKYO JAPAN A CORP. OF JAPAN reassignment MITSUI ENGINEERING & SHIPBUILDING CO., LTD., 6-4, TSUKIJI 5-CHOME, CHUO-KU, TOKYO JAPAN A CORP. OF JAPAN ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: EBATA, MAKOTO, UCHIDA, SEIJU, OTOTANI, TOHEI, DEGAWA, TORU, HASHIMOTO, AKIO, OKUYAMA, GEN, FUJIWARA, KOUZOU, SATOU, TAKASHI
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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/03—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on magnesium oxide, calcium oxide or oxide mixtures derived from dolomite
    • C04B35/057—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on magnesium oxide, calcium oxide or oxide mixtures derived from dolomite based on calcium oxide
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S29/00—Metal working
    • Y10S29/045—Titanium

Definitions

  • This invention relates to a method for melting Ti or a high-Ti alloy in CaO refractories, and more particularly relates to a method for melting Ti or a high-Ti alloy in a high-purity CaO container and high-purity CaO refractories suitable therefor.
  • Ti is a metal endowed with various characteristics such as possessing high tensile strength even in a state free from addition of any special alloy element as compared with other metallic materials, possessing as high strength as steel and aluminum alloy, exhibiting stability in various chemical environments, and showing superior corrosion resistance particularly against oxidizing acids.
  • pure Ti and Ti alloys having properties improved by combination therein of alloy elements have been taken up as subjects of the study conducted in search of methods of utility in various applications such as, for example, metallic materials for aircraft and space industry and materials for chemical industry.
  • Ti and Ti alloys have high melting points and high degrees of activity, they have been melted by the consumable electrode arc melting method or the plasma melting method. These methods, however, have the disadvantage that they consume considerably larger electric power and, for the purpose of producing homogeneous ingots, take more melting time. In the case of a melting method which uses a high-frequency induction melting furnace or a low-frequency induction melting furnace, the contamination caused by refractories exposed to the molten metal constitutes a problem in particular.
  • the high-frequency induction melting furnace uses refractories of magnesia or graphite basis. As the refractories are exposed to molten Ti, there ensues the increment of oxygen and carbon contents in the melt as indicated below.
  • Japanese Patent Application Laid-open SHO No. 59-(1984)-67,332 covers an invention relating to a Ti-Ni alloy having a Ti:Ni (mol) ratio of 1:1
  • Japanese Patent Publication SHO No. 59(1984)-40,210 covers an invention relating to a Ti type alloy having a Ti content in the range of about 36 to 47% by weight).
  • An object of the invention is to provide a method for melting pure Ti or a high-Ti alloy at an extremely high purity heretofore unattainable by the conventional melting technique with CaO refractories.
  • Another object of the ivention is to provide a method for easily melting Ti or a Ti alloy of a low oxygen content and a low carbon content exhibiting extremely high superiority with CaO refractories.
  • Yet another object of the ivention is to provide a method for easily melting Ti or a Ti alloy having an extremely homogeneous composition and warranting ease of casting and CaO refractories to be used for the method.
  • the present invention provides:
  • a method for melting Ti characterized by melting Ti in a container of a high-purity CaO material of which an inner side thereof is composed of not less than 99% by weight of CaO, not more than 0.1% by weight of SiO 2 , not more than 0.02% by weight of Fe 2 O 3 , and not more than 0.5% by weight of other metal oxides under a non-oxidizing atmosphere.
  • a method for melting a high-Ti alloy characterized by melting high-Ti alloy in a container of a high-purity CaO material of which an inner side thereof is composed of not less than 99% by weight of CaO, not more than 0.1% by weight of SiO 2 , not more than 0.02% by weight of Fe 2 O 3 , and not more than 0.5% by weight of other metal oxides under a non-oxidizing atmosphere, and CaO refractories for melting Ti or a high-Ti alloy, characterized by being composed of not less than 99% by weight of CaO, not more than 0.1% by weight of SiO 2 , not more than 0.02% by weight of Fe 2 O 3 , and not more than 0.5% by weight of other metal oxides.
  • FIG. 1 and FIG. 2 are graphs showing the results of the determinations indicated in working examples;
  • FIG. 1 shows the relation between the SiO 2 content in a crucible material obtained in Example 1 and the oxygen content of the melt, and
  • FIG. 2 shows the relation between the Fe 2 O 3 content in a crucible material obtained in Example 2 and the oxygen content of the melt.
  • FIG. 3, FIG. 4, and FIG. 5 show the relations between other metal oxides contained in the crucibles and oxygen contents in the melt.
  • the inventors continued a diligent study to elucidate the cause for the damage incurred on the furnace wall of CaO by Ti during the melting of Ti or a high-Ti alloy with the ordinary CaO container in spite of higher stability of CaO than that of TiO 2 , and consequently acquired a finding that the damage to the furnace wall is caused by a low CaO purity. They have continued a study based on this finding and have perfected the present invention.
  • high-Ti alloy refers to a Ti alloy containing one or more elements selected from among Al, Cr, Fe, Mn, Ni, Cu, V, Sn, Zr, Mo, Nb, Si, Bi, etc. and having a Ti content of not less than 65%, particularly not less than 70%, and preferably not less than 85%.
  • Ti refers to an industrially pure Ti having purity of not less than 97%. Concrete examples of "Ti” satisfying the requirement are denoted in Table 1 below. JIS means Japanese Industrial Standards.
  • the Ti or high-Ti alloy of the foregoing description is melted by the conventional method such as, for example, the high-frequency or low-frequency induction heating method using a container formed of high-purity CaO materials, which contact directly with molten metal, an inner wall thereof being composed of not less than 99% of CaO, not more than 0.1% of SiO 2 , not more than 0.02% of Fe 2 O 3 , and not more than 0.5% of other metal oxides (such as, for example, Al 2 O 3 , MgO, ZrO 2 , and TiO 2 ) under a non-oxidizing atmosphere such as a vacuum or an inert atmosphere (such as, for example, argon or helium).
  • a non-oxidizing atmosphere such as a vacuum or an inert atmosphere (such as, for example, argon or helium).
  • CaO refractories suitable for the construction of the inner side of the container to be used in melting Ti or a high-Ti alloy in accordance with the present invention, those formed of fused calcia are especially good because of high density.
  • the calcia (CaO) which is obtained by sintering calcium carbonate such as limestone, calcium hydroxide such as slaked lime, or other calcium composed is also used.
  • the CaO refractories obtained by sintering are desired to be so pure that the SiO 2 content will be not more than 0.05% and the Fe 2 O 3 content not more than 0.01%.
  • the refractories of the present invention may be irregularly shaped refractories such as stamped materials or regularly shaped refractories.
  • the irregularly shaped refractories can be used in accordance with any of the well known methods.
  • the container for the melting can be produced, for example, by applying the irregularly shaped refractories on the inner wall surface of the container.
  • nonaqueous additives such as, for example, pitch, tar, or ethanol having calcium chloride or beeswax dissolved therein
  • the regularly shaped refractories can be formed by press molding the calcia in the presence or absence of the aforementioned nonaqueous binder and optionally sintering the molded masses.
  • the regularly shaped refractories are not required to have any specifically defined shape but may bound integrally in the shape of a container such as a crucible. Otherwise, they may be molded in cubes, rectangular pipes, or other shapes enclosed in curved faces.
  • the method for melting according to the present invention comprises holding the molten alloy in a container having at least the inner side thereof formed of the refractories described above and optionally having a deoxidizer contained therein.
  • This container may be something like a crucible formed solely of the aforementioned melting refractories or a fireproof container having melting refractories (either regularly shaped or irregularly shaped refractories) applied on the inner wall surface.
  • the retention of the molten alloy in this container can be attained by pouring a melt melted in advance in a separate melting device into the container or by placing all or part of the raw materials for the alloy in the container and melting them into a melt by application of heat.
  • the molten alloy is retained in the container under a non-oxidizing atmosphere.
  • the non-oxidizing atmosphere is desired to be formed of such an inert gas as argon.
  • the high-purity CaO refractories contemplated by the present invention have extremely high stability to withstand the action of Ti enough to permit the melting of Ti or a high-Ti alloy. Further, since the high-purity CaO refractories are not only stable thermodynamically but also capable of absorbing various oxides in the molten Ti or high-Ti alloy and notably lowering the oxide contents of the melt, they permit the manufacture of Ti or Ti alloy of high purity.
  • the method of this invention for the melting of Ti or high-Ti alloy described above can be easily worked by the melting container which is formed of the high-purity CaO refractories of the invention.
  • Crucibles were produced by using CaO refractories of four different compositions, No. 1 through 4, indicated in Table 2. These crucibles were produced by mixing CaO powder and particles as raw materials, press molding the resulting mixtures, sintering the molded mixtures at 950° C. for one hour, and then sintering them further at 1700° C. for three hours.
  • a crucible was produced by using the fused calcia (CaO 99.1%) indicated in No. 2 of Table 2.
  • a crucible was produced by using the sintered product of high-purity CaO (CaO not less than 99.9%) indicated in No. 3 of Table 2. These crucibles were produced by the procedure of Example 1.
  • the raw materials for the alloy were charged and heated by the use of the same induction furnace as in Example 1 under 1 atmosphere of argon, with the melting continued until 10 minutes after the melt down. Thereafter, the melts were cast each in a mold of steel. The cast alloys were tested for oxygen content. As the result, it was found that the alloy melted in the crucible made of the fused calcia (99.1% of CaO) contained 3,450 ppm of oxygen, whereas the alloy melted in the crucible made of calcia (99.9% of CaO) contained 1,020 ppm of oxygen.
  • the alloy was melted by following the procedure of Example 4, except that the alloy had a composition of Ti-20%Ni (% by weight).
  • This alloy was produced by using sponge titanium as the raw material for Ti and Ni of purity exceeding 99.9% as the raw material for Ni. Consequently, the alloy produced by using a crucible formed of fused calcia having a CaO purity of 99.1% contained 1,350 ppm of oxygen and the alloy produced by using a crucible formed of calcia having a CaO purity exceeding 99.9% contained 520 ppm of oxygen.
  • the alloy was melted by following the procedure of Example 4, except that the alloy had a composition of Ti-33%Al (% by weight).
  • This alloy was produced by using sponge titanium as the raw material for Ti and Al of purity exceeding 99.9% as the raw material for Ni.
  • the alloy produced by using a crucible formed of fused calcia having a CaO purity of 99.1% contained 620 ppm of oxygen and the alloy produced by using a crucible formed of calcia having a CaO purity exceeding 99.9% contained 360 ppm of oxygen.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Manufacture And Refinement Of Metals (AREA)
US06/906,487 1985-09-13 1986-09-11 Method for melting Ti or a high-Ti alloy in CaO refractories Expired - Fee Related US4710481A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP60202813A JPS6263627A (ja) 1985-09-13 1985-09-13 Ｔｉ又は高Ｔｉ合金の溶製法及びそれに用いるＣａＯ耐火物
JP60-202813 1985-09-13

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5102450A (en) * 1991-08-01 1992-04-07 General Electric Company Method for melting titanium aluminide alloys in ceramic crucible
EP0530968A1 (en) * 1991-08-29 1993-03-10 General Electric Company Method for directional solidification casting of a titanium aluminide
US5766329A (en) * 1996-05-13 1998-06-16 Alliedsignal Inc. Inert calcia facecoats for investment casting of titanium and titanium-aluminide alloys
US20070267165A1 (en) * 2003-09-12 2007-11-22 Monteiro Antonio A C Process for Obtaining Y-Tial Pieces by Casting
US20070284788A1 (en) * 2004-07-29 2007-12-13 Mitsui Chemicals, Inc. Process for Producing Hollow Molded Product of Thermoplastic Resin
CN113443923A (zh) * 2020-03-24 2021-09-28 中国科学院金属研究所 一种真空感应熔炼Ti合金的CaO坩埚的制备方法

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1058856A (ja) * 1996-08-26 1998-03-03 Canon Inc テ−プ加熱装置及び製本装置

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59205432A (ja) * 1983-05-06 1984-11-21 Tohoku Metal Ind Ltd 活性金属や貴金属を含む合金の溶解法

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1058856A (ja) * 1996-08-26 1998-03-03 Canon Inc テ−プ加熱装置及び製本装置

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5102450A (en) * 1991-08-01 1992-04-07 General Electric Company Method for melting titanium aluminide alloys in ceramic crucible
EP0526159A1 (en) * 1991-08-01 1993-02-03 General Electric Company Method for melting titanium aluminide alloys
EP0530968A1 (en) * 1991-08-29 1993-03-10 General Electric Company Method for directional solidification casting of a titanium aluminide
US5766329A (en) * 1996-05-13 1998-06-16 Alliedsignal Inc. Inert calcia facecoats for investment casting of titanium and titanium-aluminide alloys
US20070267165A1 (en) * 2003-09-12 2007-11-22 Monteiro Antonio A C Process for Obtaining Y-Tial Pieces by Casting
US20070284788A1 (en) * 2004-07-29 2007-12-13 Mitsui Chemicals, Inc. Process for Producing Hollow Molded Product of Thermoplastic Resin
CN113443923A (zh) * 2020-03-24 2021-09-28 中国科学院金属研究所 一种真空感应熔炼Ti合金的CaO坩埚的制备方法

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JPS6263627A (ja) 1987-03-20
JPH0440413B2 (enrdf_load_stackoverflow) 1992-07-02

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